#include<stdio.h>
int my_strlen(char* str)
{
	int count = 0;
	while (*str)
	{
		count++;
		str++;
	}
	return count;
}
int my_strlen2(char* arr)
{
	char* str = arr;
	while (*str)
	{
		str++;
	}
	return str - arr;
}
int my_strlen3(char* p)
{
	if (*p == '\0')
	{
		return 0;
	}
	else
	{
		return 1 + my_strlen3(p + 1);
	}
}
int main()
{
	char arr[20] = "abcdef";
	int count = my_strlen(arr);
	printf("%d\n",count);
	int count2 = my_strlen2(arr);
	printf("%d\n",count2);
	int count3 = my_strlen3(arr);
	printf("%d\n",count3);
	return 0;
}